So as per the design and the mathematical expression, Xpixel lies between 0 to 12. However the value X is much higher than this. The small deviation in this X is making a significant change in Xpixel, which is making fluctuation in the animation.

To overcome with the issue, I though of increasing the GL.Ortho() bounds to GL.Ortho(0, ScreenWidthResolution, 0, ScreenHeightResolution, 1.0, -1.0); but it doesn't worked...

Anyway let me tell you a scenario of my original post. Consider following two sets for values-

X = 400 mm
ScreenWidth = 800mm
Xortho = 12

This gives Xpixel = 6

X = 450 mm
ScreenWidth = 800mm
Xortho = 12

This gives Xpixel = 6.75

My points was that even though I am making small change in the value of X, the final value of Xpixel is getting changed by a significant factor in UI.

To overcome with this issue, I thought of settingGL.Ortho() to GL.Ortho(0, ScreenWidthResolution, 0, ScreenHeightResolution, 1.0, -1.0);. By setting this, the variation in Xpixel can't be detect easily. But that doesn't work.

And, In this case, all the points lies between 0 to 12. (Since the mathematical expression is designed to do so)